As described in Japanese Unexamined Patent Application Publication No. 9-312471, a known wiring board includes a flat insulating layer having a flat upper surface, and a conductive layer with a large surface area on the upper surface of the insulating layer. Also, a known electronic package includes an electronic device mounted on the upper surface of such a wiring board. A conductive layer is formed on the wiring board by screen printing. The conductive layer formed by screen printing is likely to have raised two ends in a cross-sectional view.
A demand is typically increasing for thinner and multi-layered wiring boards. A conductive layer with peripheral portions raised higher than its central portion in a cross-sectional view can cause the upper surface of the wiring board to deform, on which an electronic device is not easily mountable. The mountability is to be improved.